A numerical investigation of non-spherical rebounding bubbles

Abstract

The motion of buoyant transient cavities with non-condensible contents is investigated numerically using a boundary-integral method. The bubble contents are described by an adiabatic gas law. Motion is considered in the neighbourhood of a rigid boundary, in an axisymmetric geometry. We investigate whether the non-condensible contents will resist the formation of jets. It is found that jets form upon collapse and, in general, completely penetrate the bubble before it rebounds, but circumstances are identified under which the non-spherical bubble will rebound prior to this occurrence. In these cases the bulk of the jet growth occurs upon rebound. Furthermore, the interaction between the buoyancy force causing jet formation upwards, and the Bjerknes attraction of the rigid boundary causing jet formation towards it, is investigated and general principles discussed which allow the behaviour to be interpreted. The concept of the Kelvin impulse is utilized.

The Influence of Structural Deformation on Water Jet Impact Loading

“…In the rigid fixed body case the bubble collapses without significant jet formation, then forms a very thin jet during rebound. Best & Kucera (1992) found similar results near solid walls. Lauterborn (1981) has observed jet formation during rebound using laser-generated bubbles.…”

Modelling cavitation erosion using fluid–material interaction simulations

“…We consider an initially spherical bubble of radius 50 mm, located at a distance of X ¼ 1.5 mm from a flat material surface and subject it to a time-varying pressure field as represented in figure 2 and expressed as follows: This imposed pressure variation is different from that used in many classical studies on bubble collapse near a wall and where a bubble with a maximum radius is suddenly subjected to a pressure higher than the internal pressure such as in [71][72][73][74]. Here, bubble growth is included (this allows one to include standoff distances smaller than the bubble maximum radius and covers a large range of applications), and the time-varying pressure field represents for example the pressure encountered by a bubble nucleus captured in the shear layer of a cavitating jet.…”

Particle tracking velocimetry of the flow field around a collapsing cavitation bubble

“…Also, erosion and pit formation on surfaces caused by collapsing bubbles have been studied by correlating their dynamics with damage spots on the surface (Philipp and Lauterborn 1998;Isselin et al 1998;Tomita and Shima 1986). Numerical work on the interaction of a bubble with nearby boundaries using the boundary-integral method (Blake et al 1986;Best and Kucera 1992;Robinson et al 2001) has generally shown good agreement with experimental observations. Computations were performed up to the last stages of collapse (Best 1993;Zhang et al 1993;Brujan et al 2002) and beyond (Lee et al 2007).…”